Evapotranspiration from cranberry compared with the equilibrium rate1

Abstract

The rate of evapotranspiration from a mature cranberry bed in Wisconsin was measured using infrared thermometry. Values ranged from 0.8 to 6.2 mm d−1, which were on average 1.05 of the equilibrium evaporation rate. These results are in good agreement with those measured earlier in Wisconsin by the Bowen-ratio technique. Estimates of stomatal conductance were extracted from the data, yielding values of at least 0.2–0.3 mol m−2 s−1, substantially higher than earlier reports for cranberry but typical of uncultivated plants. Our results give us good confidence that cranberry evapotranspiration in the continental climate of Wisconsin, at least, can be estimated from the equilibrium evaporation rate, i.e., the Priestley–Taylor potential rate, with α = 1.05.